The statements in this section merely provide background information related to the present disclosure and may not constitute prior art.
Minor shift quality issues are sometimes found in new production vehicles due in part to variation in engine and automatic transmission manufacturing. Shift quality issues can be one of the most common complaints of new production vehicle customers. A significant portion of these shift quality issue complaints occur due to an event that only occurs once or twice early in the owner's driving experience. These shift quality issue complaints can include the transmission feeling rough and the transmission hesitating. Often times, these shift quality events cannot be duplicated at a dealership when the vehicle is brought in by the customer for repair.
Review of such shift quality events has indicated that most of these shift quality issues occur because the controller for the automatic transmission has not yet learned how to compensate for manufacturing and part to part variations. Such shift quality issues only occur once or twice early in the ownership experience because the shift quality issues are generally fixed by the normal automatic transmission adaptation process that occurs as the vehicle is driven in the early stages of vehicle ownership.
Methods have been developed to test for and fix shift quality issues of a transmission before ownership of the vehicle is transferred to the customer. Such methods include bedding-in the automatic transmission of the vehicle prior to delivery of the vehicle to the end-customer by running the vehicle through a set procedure to allow the transmission control unit and engine control unit to learn and compensate for manufacturing and part to part variations. Generally, the set procedure for such bedding-in methods requires that an operator run the transmission through all of the transmission gears at specific time and engine speed intervals. Additionally, the set procedure includes running the transmission through all of the transmission gears multiple times. An exemplary system for bedding in a vehicle is disclosed in U.S. Pat. No. 8,874,336 B2.
We have discovered that in some cases the number of times that the transmission is run through the gears is in excess of what is required for the transmission controller and engine controller to adapt to the variations of the transmission. This results in wasted production time. We have also discovered that in other cases the number of times the transmission is run through its gears is not enough to allow the transmission controller and engine controller to learn and adapt to the variations of the transmission. In such situations only the subjective experience and perception of the test operator are relied upon to determine if the vehicle transmission still has shift quality issues.